Protection Engineering Basics and Schemes Protection Engineering | Page 51

120 0 , This PT must be ground and is place with
under test PT
 Connect Proven VT with your Phase rotation
meter, and place A phase of phase rotation
meter at A phase of under test PT, if polarity
correct meter will show 0 reading or some but
little amount of voltage presence say 1-2% of
rated output secondary voltage. Do same with all
other phases. This will not exactly detect the
correct phase sequence
 We also can do it by other way, we can remove B
and C phase HRC fuses , and then check A phase
, if phase sequence is correct then only phase
show Voltage, B and C phase will show Zero or
residual voltage
 Remember once you connected your phase
rotation meter, you just have to move your dial
on particular phase voltage measurement.
You can see real time connection drawing of this test
below
pg. 51